Nuclear Factor-kappaB in Ovarian Cancer

NF-kB通路促进癌细胞的存活。我对卵巢癌的研究开始于描述这种疾病中NF-kB的激活状态和生物学相关性。转录因子的NF-κ B家族广泛表达。NF-kB信号通路与卵巢癌有关，但NF-kB信号通路在卵巢癌中的意义和机制尚不清楚。有先例表明NF-kB是癌症中的关键信号传导机制。我最初假设NF-kB通路在卵巢癌中过度激活，具有更强的侵袭性。NF-κ B通路参与卵巢癌细胞的体外增殖和细胞因子分泌，并导致卵巢癌细胞株的化疗耐药性。因此，我试图确定NF-κ B通路蛋白在原发性卵巢癌组织中的表达模式和预后相关性。我证明了诊断时NF-κ B亚单位p50的过度表达传达了这些患者的不良结局。NF-kB在卵巢癌中的生物学相关性是在我的实验室建立的。在证明了卵巢癌中NF-κ B机制的协调存在后，我试图调节其活性。标记NF-κ B抑制剂（IkB），以便在IkB激酶（IKK）特异性诱导磷酸化后通过蛋白酶体降解。因此，靶向抑制IKK可以分离NF-kB作为卵巢癌发病机制。抑制IKKb可影响卵巢癌细胞系的生长、粘附、侵袭和细胞因子分泌。我开发了一个IKKb信号在卵巢癌中的基因表达签名，使用IKKb的药理学和遗传操作。基于卵巢癌特异性靶基因的已知功能，该特征使我能够深入了解NF-kB在卵巢癌中的结果，并使我能够探索已建立的卵巢癌数据库，以估计NF-kB信号传导对卵巢癌患者生存的相对影响。较高的NF-kB活性传达了更差的结果，表明IKKb的调节可能使肿瘤显示靶基因表达升高的患者受益。这项工作的一个关键发现是NF-κ B信号的组织特异性。在卵巢癌中实验定义的9个基因签名与我之前在多发性骨髓瘤中确定的11个基因完全不同。该项目的总体目标是剖析卵巢癌中NF-kB信号传导的分子结构，旨在开发NF-kB依赖性的生物标志物和治疗干预的新点。在2013财年，我们发表了一项研究，确定IKK β在卵巢癌的转移和侵袭中起作用。我们还完成了两个shRNA文库筛选，一个与IKK β抑制剂组合，另一个与针对IKK β的shRNA组合。这些研究确定了卵巢癌中NF-κ B通路之间的新相互作用。与IKK β结合，我们发现caspase 8在保护细胞免于坏死性凋亡方面是合作的。这项工作将在2014财年提交出版。结合IKK3，我们发现CHEK 1通过阻止IKK3驱动的细胞周期来保护细胞免受灾难性的DNA损伤。这项工作也将在2014财年提交。从治疗的角度来看，我们已经开始了一项使用SMAC模拟物birinapant治疗复发性和难治性卵巢癌的2期临床试验。这种药物靶向cIAP 1降解，从而中断NF-κ B信号传导并触发细胞凋亡。我们正在收集血液，血清和肿瘤活检从病人在这个临床试验，并将分析他们的变化，NF-κ B和细胞凋亡激活状态。

The NF-kB pathway promotes survival of cancer cells. My research in ovarian cancer began with characterizing the activation state and biological relevance of NF-kB in this disease. The NF-kB family of transcription factors is ubiquitously expressed. NF-kB signaling has been implicated in ovarian cancer, but the significance and mechanism of NF-kB signaling in ovarian cancer is unknown. There is precedent to propose that NF-kB is a critical signaling mechanism in cancer. I initially hypothesized that the NF-kB pathway is over-activated in ovarian cancers with more aggressive behavior. The NF-kB pathway was implicated in ovarian cancer proliferation and cytokine secretion in vitro, and contributed to chemoresistance of ovarian cancer cell lines. I therefore sought to determine the expression patterns and prognostic associations of NF-kB pathway proteins in primary ovarian cancer tissues. I demonstrated that overexpression of the NF-kB subunit p50 at diagnosis conveyed poor outcome in these patients. The biological relevance of NF-kB in ovarian cancer was established in my laboratory. Having demonstrated the coordinate presence of NF-kB machinery in ovarian cancers, I sought to modulate its activity. Inhibitors of NF-kB (IkBs) are tagged for degradation through the proteasome upon specific inducible phosphorylation by IkB kinases (IKKs). Therefore, targeted inhibition of IKKs could isolate NF-kB as a mechanism for ovarian cancer pathogenesis. A subset of ovarian cancer cell lines was affected by inhibition of IKKb in properties of growth, adhesion, invasion and cytokine secretion. I developed a gene expression signature of IKKb signaling in ovarian cancer using both pharmacologic and genetic manipulation of IKKb. This signature gave insight into the results of NF-kB in ovarian cancer, based on known functions of the ovarian cancer-specific target genes, and allowed me to probe established ovarian cancer databases in order to estimate the relative impact of NF-kB signaling on the survival of women with ovarian cancer. Higher NF-kB activity conveyed a worse outcome, suggesting that modulation of IKKb might benefit patients whose tumors showed elevated target gene expression. A key discovery from this work was the tissue specificity of NF-kB signaling. The 9-gene signature experimentally defined in ovarian cancer was completely different from the 11 genes I previously identified in multiple myeloma. The overall goal of this project is to dissect the molecular structure of NF-kB signaling in ovarian cancer, with the intent to develop biomarkers of dependence on NF-kB, and novel points of therapeutic intervention. In FY 2013 we published a study identifying IKKepsilon as instrumental in the metastasis and invasion of ovarian cancer. We also completed two shRNA library screens, one in combination with an inhibitor of IKKbeta, and another in combination with shRNA against IKKepsilon. These studies identified novel interactions between the NF-kB pathway in ovarian cancer. In combination with IKKbeta, we found caspase 8 to be cooperative in protecting the cells from necroptosis. This work will be submitted for publication during FY 2014. In combination with IKKepsilon, we discovered that CHEK1 protected the cells from catastrophic DNA damage by stalling the cell cycle driven by IKKepsilon. This work will also be submitted in FY 2014. From a therapeutic standpoint, we have begun a phase 2 clinical trial using the SMAC mimetic birinapant in women with relapsed and refractory ovarian cancer. This drug targets cIAP1 for degradation, and thus interrupts NF-kB signaling and triggers apoptosis. We are collecting blood, serum, and tumor biopsies from patients on this clinical trial and will analyze them for changes in NF-kB and apoptosis activation states.